When a brand changes its domain, does AI notice?

A retired domain is a domain a brand moved its main website away from; in every pair we studied, the retired domain still redirects to the current site. Across 15 brands with verified domain changes, AI engines produced 12,875 citations that pointed at either the current domain or the retired one. 2,524 of those citations, or 19.6%, used the retired domain.

Redirects keep the links working, but readers still see the old domain. That share differs sharply between recent and older domain changes.

Two brands in the set changed domains in 2024: X moved from twitter.com to x.com in May 2024, and The Times moved from thetimes.co.uk to thetimes.com the same year. For those two, 2,522 of 10,257 own-site citations, or 24.6%, used the retired domain.

The other 13 brands changed domains in 2022 or earlier. For them, the retired domain appeared in 2 of 2,618 citations, or 0.08%. AI does notice a domain change, but in this data the noticing takes years, not weeks.

Nine pairs had at least 30 own-site citations in the window. Only the two 2024 changes show any retired-domain share: The Times at 33.6% and X at 19.8%. The seven brands with older changes (KnowledgeBase, ChatBot, Old Navy, Warner Bros. Discovery, Fastmail, Disneyland Resort, and UT Southwestern) sit at exactly zero.

The zeros are measured, not assumed: for all seven of those retired domains, not a single citation was ever recorded anywhere in the index.

Across all 15 pairs, ChatGPT used the retired domain in 29.7% of its own-site citations and ChatGPT Search in 23.6%. Google AI Overviews used it in 2.3% and Google AI Mode in 0.07%. Combined, OpenAI's engines sat at 28.9% and Google's at 1.6%.

The engines differed even though the old domains redirected to the new sites. This study cannot tell us whether the difference comes from search indexing, stored model knowledge, or another part of the citation process.

X switched its main domain from twitter.com to x.com in May 2024. In our legacy-engine window (ChatGPT and Google AI Overviews, through May 23, 2026), 1,332 of 5,809 citations of X's site, or 22.9%, still said twitter.com, two years after the switch.

Then the tracked engines changed. In the current-era window (ChatGPT Search and Google AI Mode, from May 24, 2026), twitter.com appeared in 0 of 908 citations of X's site. The old domain did not fade out gradually; it dropped to zero at the switch to the newer engines. The Times pair below shows the same switch did not clear its retired domain, so this is an observation about X's citations, not a guarantee the newer engines make.

The Times moved from thetimes.co.uk to thetimes.com in 2024, and its retired domain has not dropped to zero on the current engines. In the current-era window, ChatGPT Search used thetimes.co.uk in 264 of 654 citations of The Times' site, or 40.4%. Google AI Mode used it in 0 of 233.

Same publisher, same window, same redirects, and one engine prints the retired domain 4 times in 10 while the other never does. Whether AI notices your domain change is not one question; it is one question per engine.

Monthly retired-domain shares for the two 2024 changes, January through August 2026: X ran between 14.3% and 28.6% through March, fell to 1.6% in April, and has been 0% every month since the engine change in late May. The Times ran between 38.7% and 51.0% in the first quarter and still sat at 18.8% in August.

There is no smooth decay curve here. The X share collapsed when measurement moved to search-grounded engines; the Times share persisted straight through the same change. May 2026 is the transition month between engine generations and carries very low volume for both pairs.

The seven named brands that changed domains in 2022 or earlier collected 2,566 own-site citations in the window, every one on the current domain. KnowledgeBase (formerly knowledgebase.ai) drew 855, ChatBot (formerly botengine.ai) 766, Old Navy 421, Warner Bros. Discovery 215, Fastmail (formerly fastmail.fm) 170, Disneyland Resort 83, and UT Southwestern Medical Center 56.

Given enough time, AI engines converge on the new domain completely, including for brands whose old domain was a different name entirely.

The pair list is manual. From 426 verified first-party domain records covering 116 brands in the public Parse index, we kept the 15 brands where public records document a move of the main site from one domain to another; most verified records are regional storefronts, technical hosts, or short-link domains and were excluded. The verified records carry no real-world change dates, so this is a cross-sectional study of a stated window, not an event study around each migration. Six pairs had fewer than 30 combined citations and are aggregated, never named. The Times pair has near-zero volume before January 2026, so the trend starts there.

Counts are by hostname: a citation counts as retired-domain when the printed link's host is the retired domain, whatever the answer topic. Every retired domain in the set redirects to the current site, so these are working links with an outdated name, not broken links. As a check, recomputing the headline through an independent calculation grouped by domain, using a different rule for removing duplicates gives 17.6%, the same rough 1-in-5 result.

If you changed domains recently, assume AI answers are still printing the old name. Check citations of your site on each engine separately: in this data Google AI Mode had effectively finished switching (1 retired citation in 1,338) while ChatGPT and ChatGPT Search were still at roughly a quarter retired.

Keep the redirects from the old domain alive indefinitely: in this data they are what kept 2,524 retired-domain citations working. Update the copies of your URLs you control (profiles, directories, documentation, partner pages), because engines reproduce old links as they find them. Then re-run the same check quarterly: the seven older migrations in this study show the retired share does reach zero.